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  <div class="section" id="module-codeop">
<span id="codeop-compile-python-code"></span><h1>30.2. <a class="reference internal" href="#module-codeop" title="codeop: Compile (possibly incomplete) Python code."><code class="xref py py-mod docutils literal"><span class="pre">codeop</span></code></a> — Compile Python code<a class="headerlink" href="#module-codeop" title="Permalink to this headline">¶</a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.6/Lib/codeop.py">Lib/codeop.py</a></p>
<hr class="docutils" />
<p>The <a class="reference internal" href="#module-codeop" title="codeop: Compile (possibly incomplete) Python code."><code class="xref py py-mod docutils literal"><span class="pre">codeop</span></code></a> module provides utilities upon which the Python
read-eval-print loop can be emulated, as is done in the <a class="reference internal" href="code.html#module-code" title="code: Facilities to implement read-eval-print loops."><code class="xref py py-mod docutils literal"><span class="pre">code</span></code></a> module.  As
a result, you probably don’t want to use the module directly; if you want to
include such a loop in your program you probably want to use the <a class="reference internal" href="code.html#module-code" title="code: Facilities to implement read-eval-print loops."><code class="xref py py-mod docutils literal"><span class="pre">code</span></code></a>
module instead.</p>
<p>There are two parts to this job:</p>
<ol class="arabic simple">
<li>Being able to tell if a line of input completes a Python  statement: in
short, telling whether to print ‘<code class="docutils literal"><span class="pre">&gt;&gt;&gt;</span></code>’ or ‘<code class="docutils literal"><span class="pre">...</span></code>’ next.</li>
<li>Remembering which future statements the user has entered, so  subsequent
input can be compiled with these in effect.</li>
</ol>
<p>The <a class="reference internal" href="#module-codeop" title="codeop: Compile (possibly incomplete) Python code."><code class="xref py py-mod docutils literal"><span class="pre">codeop</span></code></a> module provides a way of doing each of these things, and a way
of doing them both.</p>
<p>To do just the former:</p>
<dl class="function">
<dt id="codeop.compile_command">
<code class="descclassname">codeop.</code><code class="descname">compile_command</code><span class="sig-paren">(</span><em>source</em>, <em>filename=&quot;&lt;input&gt;&quot;</em>, <em>symbol=&quot;single&quot;</em><span class="sig-paren">)</span><a class="headerlink" href="#codeop.compile_command" title="Permalink to this definition">¶</a></dt>
<dd><p>Tries to compile <em>source</em>, which should be a string of Python code and return a
code object if <em>source</em> is valid Python code. In that case, the filename
attribute of the code object will be <em>filename</em>, which defaults to
<code class="docutils literal"><span class="pre">'&lt;input&gt;'</span></code>. Returns <code class="docutils literal"><span class="pre">None</span></code> if <em>source</em> is <em>not</em> valid Python code, but is a
prefix of valid Python code.</p>
<p>If there is a problem with <em>source</em>, an exception will be raised.
<a class="reference internal" href="exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal"><span class="pre">SyntaxError</span></code></a> is raised if there is invalid Python syntax, and
<a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal"><span class="pre">OverflowError</span></code></a> or <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal"><span class="pre">ValueError</span></code></a> if there is an invalid literal.</p>
<p>The <em>symbol</em> argument determines whether <em>source</em> is compiled as a statement
(<code class="docutils literal"><span class="pre">'single'</span></code>, the default) or as an <a class="reference internal" href="../glossary.html#term-expression"><span class="xref std std-term">expression</span></a> (<code class="docutils literal"><span class="pre">'eval'</span></code>).  Any
other value will cause <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal"><span class="pre">ValueError</span></code></a> to  be raised.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">It is possible (but not likely) that the parser stops parsing with a
successful outcome before reaching the end of the source; in this case,
trailing symbols may be ignored instead of causing an error.  For example,
a backslash followed by two newlines may be followed by arbitrary garbage.
This will be fixed once the API for the parser is better.</p>
</div>
</dd></dl>

<dl class="class">
<dt id="codeop.Compile">
<em class="property">class </em><code class="descclassname">codeop.</code><code class="descname">Compile</code><a class="headerlink" href="#codeop.Compile" title="Permalink to this definition">¶</a></dt>
<dd><p>Instances of this class have <a class="reference internal" href="../reference/datamodel.html#object.__call__" title="object.__call__"><code class="xref py py-meth docutils literal"><span class="pre">__call__()</span></code></a> methods identical in signature to
the built-in function <a class="reference internal" href="functions.html#compile" title="compile"><code class="xref py py-func docutils literal"><span class="pre">compile()</span></code></a>, but with the difference that if the
instance compiles program text containing a <a class="reference internal" href="__future__.html#module-__future__" title="__future__: Future statement definitions"><code class="xref py py-mod docutils literal"><span class="pre">__future__</span></code></a> statement, the
instance ‘remembers’ and compiles all subsequent program texts with the
statement in force.</p>
</dd></dl>

<dl class="class">
<dt id="codeop.CommandCompiler">
<em class="property">class </em><code class="descclassname">codeop.</code><code class="descname">CommandCompiler</code><a class="headerlink" href="#codeop.CommandCompiler" title="Permalink to this definition">¶</a></dt>
<dd><p>Instances of this class have <a class="reference internal" href="../reference/datamodel.html#object.__call__" title="object.__call__"><code class="xref py py-meth docutils literal"><span class="pre">__call__()</span></code></a> methods identical in signature to
<a class="reference internal" href="#codeop.compile_command" title="codeop.compile_command"><code class="xref py py-func docutils literal"><span class="pre">compile_command()</span></code></a>; the difference is that if the instance compiles program
text containing a <code class="docutils literal"><span class="pre">__future__</span></code> statement, the instance ‘remembers’ and
compiles all subsequent program texts with the statement in force.</p>
</dd></dl>

</div>


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